Doxycycline hyclate 20 mg bid is an effective maintenance dosage in patients with inflammatory acne. Twelve subjects aged 14 to 36, both men and women, completed a 16-week study to demonstrate the effectiveness of submicrobial dosing of doxycycline hyclate. Seventeen subjects were screened, and three withdrew before receiving any medication. The subjects received doxycycline hyclate 100 mg daily for eight weeks. One subject withdrew due to unrelated side effects. Eleven subjects had a 50% reduction of lesions at eight weeks, which qualified them to enter the second eight-week phase of the study. This group received either doxycycline hyclate 20 mg bid or placebo. The six subjects receiving doxycycline hyclate 20 mg bid maintained their improvement, while the placebo group did not.